dss.c

   1 #include <string.h>
   2 #include <stdlib.h>
   3 #include <stdarg.h>
   4 #include <assert.h>
   5 #include <errno.h>
   6 #include <sys/types.h>
   7 #include <signal.h>
   8 #include <ctype.h>
   9 #include <sys/stat.h>
  10 #include <unistd.h>
  11 #include <inttypes.h>
  12 #include <sys/time.h>
  13 #include <time.h>
  14 #include <sys/wait.h>
  15 #include <fnmatch.h>
  16 #include <limits.h>
  17
  18
  19 #include "gcc-compat.h"
  20 #include "cmdline.h"
  21 #include "log.h"
  22 #include "string.h"
  23 #include "error.h"
  24 #include "fd.h"
  25 #include "exec.h"
  26 #include "daemon.h"
  27 #include "signal.h"
  28 #include "df.h"
  29 #include "time.h"
  30
  31
  32 struct gengetopt_args_info conf;
  33 char *dss_error_txt = NULL;
  34 static FILE *logfile;
  35 static int signal_pipe;
  36
  37 /** Process id of current rsync process. */
  38 static pid_t rsync_pid;
  39 /** Whether the rsync process is currently stopped */
  40 static int rsync_stopped;
  41 /** Process id of current rm process. */
  42 static pid_t rm_pid;
  43 /** When the next snapshot is due. */
  44 struct timeval next_snapshot_time;
  45 /* Creation time of the snapshot currently being created. */
  46 int64_t current_snapshot_creation_time;
  47
  48
  49 DEFINE_DSS_ERRLIST;
  50
  51
  52 /* a litte cpp magic helps to DRY */
  53 #define COMMANDS \
  54         COMMAND(ls) \
  55         COMMAND(create) \
  56         COMMAND(prune) \
  57         COMMAND(run)
  58 #define COMMAND(x) int com_ ##x(void);
  59 COMMANDS
  60 #undef COMMAND
  61 #define COMMAND(x) if (conf.x ##_given) return com_ ##x();
  62 int call_command_handler(void)
  63 {
  64         COMMANDS
  65         DSS_EMERG_LOG("BUG: did not find command handler\n");
  66         exit(EXIT_FAILURE);
  67 }
  68 #undef COMMAND
  69 #undef COMMANDS
  70
  71 /*
  72  * complete, not being deleted: 1204565370-1204565371.Sun_Mar_02_2008_14_33-Sun_Mar_02_2008_14_43
  73  * complete, being deleted: 1204565370-1204565371.being_deleted
  74  * incomplete, not being deleted: 1204565370-incomplete
  75  * incomplete, being deleted: 1204565370-incomplete.being_deleted
  76  */
  77 enum snapshot_status_flags {
  78         /** The rsync process terminated successfully. */
  79         SS_COMPLETE = 1,
  80         /** The rm process is running to remove this snapshot. */
  81         SS_BEING_DELETED = 2,
  82 };
  83
  84 struct snapshot {
  85         char *name;
  86         int64_t creation_time;
  87         int64_t completion_time;
  88         enum snapshot_status_flags flags;
  89         unsigned interval;
  90 };
  91
  92 /*
  93  * An edge snapshot is either the oldest one or the newest one.
  94  *
  95  * We need to find either of them occasionally: The create code
  96  * needs to know the newest snapshot because that is the one
  97  * used as the link destination dir. The pruning code needs to
  98  * find the oldest one in case disk space becomes low.
  99  */
 100 struct edge_snapshot_data {
 101         int64_t now;
 102         struct snapshot snap;
 103 };
 104
 105 __printf_2_3 void dss_log(int ll, const char* fmt,...)
 106 {
 107         va_list argp;
 108         FILE *outfd;
 109         struct tm *tm;
 110         time_t t1;
 111         char str[255] = "";
 112
 113         if (ll < conf.loglevel_arg)
 114                 return;
 115         outfd = logfile? logfile : stderr;
 116         time(&t1);
 117         tm = localtime(&t1);
 118         strftime(str, sizeof(str), "%b %d %H:%M:%S", tm);
 119         fprintf(outfd, "%s ", str);
 120         if (conf.loglevel_arg <= INFO)
 121                 fprintf(outfd, "%i: ", ll);
 122         va_start(argp, fmt);
 123         vfprintf(outfd, fmt, argp);
 124         va_end(argp);
 125 }
 126
 127 /**
 128  * Print a message either to stdout or to the log file.
 129  */
 130 __printf_1_2 void dss_msg(const char* fmt,...)
 131 {
 132         FILE *outfd = conf.daemon_given? logfile : stdout;
 133         va_list argp;
 134         va_start(argp, fmt);
 135         vfprintf(outfd, fmt, argp);
 136         va_end(argp);
 137 }
 138
 139 /**
 140  * Return the desired number of snapshots of an interval.
 141  */
 142 unsigned num_snapshots(int interval)
 143 {
 144         unsigned n;
 145
 146         assert(interval >= 0);
 147
 148         if (interval >= conf.num_intervals_arg)
 149                 return 0;
 150         n = conf.num_intervals_arg - interval - 1;
 151         return 1 << n;
 152 }
 153
 154 /* return: Whether dirname is a snapshot directory (0: no, 1: yes) */
 155 int is_snapshot(const char *dirname, int64_t now, struct snapshot *s)
 156 {
 157         int i, ret;
 158         char *dash, *dot, *tmp;
 159         int64_t num;
 160
 161         assert(dirname);
 162         dash = strchr(dirname, '-');
 163         if (!dash || !dash[1] || dash == dirname)
 164                 return 0;
 165         for (i = 0; dirname[i] != '-'; i++)
 166                 if (!isdigit(dirname[i]))
 167                         return 0;
 168         tmp = dss_strdup(dirname);
 169         tmp[i] = '\0';
 170         ret = dss_atoi64(tmp, &num);
 171         free(tmp);
 172         if (ret < 0) {
 173                 free(dss_error_txt);
 174                 return 0;
 175         }
 176         assert(num >= 0);
 177         if (num > now)
 178                 return 0;
 179         s->creation_time = num;
 180         //DSS_DEBUG_LOG("%s start time: %lli\n", dirname, (long long)s->creation_time);
 181         s->interval = (long long) ((now - s->creation_time)
 182                 / conf.unit_interval_arg / 24 / 3600);
 183         if (!strcmp(dash + 1, "incomplete")) {
 184                 s->completion_time = -1;
 185                 s->flags = 0; /* neither complete, nor being deleted */
 186                 goto success;
 187         }
 188         if (!strcmp(dash + 1, "incomplete.being_deleted")) {
 189                 s->completion_time = -1;
 190                 s->flags = SS_BEING_DELETED; /* mot cpmplete, being deleted */
 191                 goto success;
 192         }
 193         tmp = dash + 1;
 194         dot = strchr(tmp, '.');
 195         if (!dot || !dot[1] || dot == tmp)
 196                 return 0;
 197         for (i = 0; tmp[i] != '.'; i++)
 198                 if (!isdigit(tmp[i]))
 199                         return 0;
 200         tmp = dss_strdup(dash + 1);
 201         tmp[i] = '\0';
 202         ret = dss_atoi64(tmp, &num);
 203         free(tmp);
 204         if (ret < 0) {
 205                 free(dss_error_txt);
 206                 return 0;
 207         }
 208         if (num > now)
 209                 return 0;
 210         s->completion_time = num;
 211         s->flags = SS_COMPLETE;
 212         if (!strcmp(dot + 1, "being_deleted"))
 213                 s->flags |= SS_BEING_DELETED;
 214 success:
 215         s->name = dss_strdup(dirname);
 216         return 1;
 217 }
 218
 219 int64_t get_current_time(void)
 220 {
 221         time_t now;
 222         time(&now);
 223         DSS_DEBUG_LOG("now: %lli\n", (long long) now);
 224         return (int64_t)now;
 225 }
 226
 227 char *incomplete_name(int64_t start)
 228 {
 229         return make_message("%lli-incomplete", (long long)start);
 230 }
 231
 232 char *being_deleted_name(struct snapshot *s)
 233 {
 234         if (s->flags & SS_COMPLETE)
 235                 return make_message("%lli-%lli.being_deleted",
 236                         (long long)s->creation_time,
 237                         (long long)s->completion_time);
 238         return make_message("%lli-incomplete.being_deleted",
 239                 (long long)s->creation_time);
 240 }
 241
 242 int complete_name(int64_t start, int64_t end, char **result)
 243 {
 244         struct tm start_tm, end_tm;
 245         time_t *start_seconds = (time_t *) (uint64_t *)&start; /* STFU, gcc */
 246         time_t *end_seconds = (time_t *) (uint64_t *)&end; /* STFU, gcc */
 247         char start_str[200], end_str[200];
 248
 249         if (!localtime_r(start_seconds, &start_tm)) {
 250                 make_err_msg("%lli", (long long)start);
 251                 return -E_LOCALTIME;
 252         }
 253         if (!localtime_r(end_seconds, &end_tm)) {
 254                 make_err_msg("%lli", (long long)end);
 255                 return -E_LOCALTIME;
 256         }
 257         if (!strftime(start_str, sizeof(start_str), "%a_%b_%d_%Y_%H_%M_%S", &start_tm)) {
 258                 make_err_msg("%lli", (long long)start);
 259                 return -E_STRFTIME;
 260         }
 261         if (!strftime(end_str, sizeof(end_str), "%a_%b_%d_%Y_%H_%M_%S", &end_tm)) {
 262                 make_err_msg("%lli", (long long)end);
 263                 return -E_STRFTIME;
 264         }
 265         *result = make_message("%lli-%lli.%s-%s", (long long) start, (long long) end,
 266                 start_str, end_str);
 267         return 1;
 268 }
 269
 270 struct snapshot_list {
 271         int64_t now;
 272         unsigned num_snapshots;
 273         unsigned array_size;
 274         struct snapshot **snapshots;
 275         /**
 276          * Array of size num_intervals + 1
 277          *
 278          * It contains the number of snapshots in each interval. interval_count[num_intervals]
 279          * is the number of snapshots which belong to any interval greater than num_intervals.
 280          */
 281         unsigned *interval_count;
 282 };
 283
 284 #define FOR_EACH_SNAPSHOT(s, i, sl) \
 285         for ((i) = 0; (i) < (sl)->num_snapshots && ((s) = (sl)->snapshots[(i)]); (i)++)
 286
 287
 288
 289 #define NUM_COMPARE(x, y) ((int)((x) < (y)) - (int)((x) > (y)))
 290
 291 static int compare_snapshots(const void *a, const void *b)
 292 {
 293         struct snapshot *s1 = *(struct snapshot **)a;
 294         struct snapshot *s2 = *(struct snapshot **)b;
 295         return NUM_COMPARE(s2->creation_time, s1->creation_time);
 296 }
 297
 298 /** Compute the minimum of \a a and \a b. */
 299 #define DSS_MIN(a,b) ((a) < (b) ? (a) : (b))
 300
 301 int add_snapshot(const char *dirname, void *private)
 302 {
 303         struct snapshot_list *sl = private;
 304         struct snapshot s;
 305         int ret = is_snapshot(dirname, sl->now, &s);
 306
 307         if (!ret)
 308                 return 1;
 309         if (sl->num_snapshots >= sl->array_size) {
 310                 sl->array_size = 2 * sl->array_size + 1;
 311                 sl->snapshots = dss_realloc(sl->snapshots,
 312                         sl->array_size * sizeof(struct snapshot *));
 313         }
 314         sl->snapshots[sl->num_snapshots] = dss_malloc(sizeof(struct snapshot));
 315         *(sl->snapshots[sl->num_snapshots]) = s;
 316         sl->interval_count[DSS_MIN(s.interval, conf.num_intervals_arg)]++;
 317         sl->num_snapshots++;
 318         return 1;
 319 }
 320
 321 void get_snapshot_list(struct snapshot_list *sl)
 322 {
 323         sl->now = get_current_time();
 324         sl->num_snapshots = 0;
 325         sl->array_size = 0;
 326         sl->snapshots = NULL;
 327         sl->interval_count = dss_calloc((conf.num_intervals_arg + 1) * sizeof(unsigned));
 328         for_each_subdir(add_snapshot, sl);
 329         qsort(sl->snapshots, sl->num_snapshots, sizeof(struct snapshot *),
 330                 compare_snapshots);
 331 }
 332
 333 void free_snapshot_list(struct snapshot_list *sl)
 334 {
 335         int i;
 336         struct snapshot *s;
 337
 338         FOR_EACH_SNAPSHOT(s, i, sl) {
 339                 free(s->name);
 340                 free(s);
 341         }
 342         free(sl->interval_count);
 343         sl->interval_count = NULL;
 344         free(sl->snapshots);
 345         sl->snapshots = NULL;
 346         sl->num_snapshots = 0;
 347 }
 348
 349 void stop_rsync_process(void)
 350 {
 351         if (!rsync_pid || rsync_stopped)
 352                 return;
 353         kill(SIGSTOP, rsync_pid);
 354         rsync_stopped = 1;
 355 }
 356
 357 void restart_rsync_process(void)
 358 {
 359         if (!rsync_pid || !rsync_stopped)
 360                 return;
 361         kill (SIGCONT, rsync_pid);
 362         rsync_stopped = 0;
 363 }
 364
 365 /**
 366  * Print a log message about the exit status of a child.
 367  */
 368 void log_termination_msg(pid_t pid, int status)
 369 {
 370         if (WIFEXITED(status))
 371                 DSS_INFO_LOG("child %i exited. Exit status: %i\n", (int)pid,
 372                         WEXITSTATUS(status));
 373         else if (WIFSIGNALED(status))
 374                 DSS_NOTICE_LOG("child %i was killed by signal %i\n", (int)pid,
 375                         WTERMSIG(status));
 376         else
 377                 DSS_WARNING_LOG("child %i terminated abormally\n", (int)pid);
 378 }
 379
 380 int wait_for_process(pid_t pid, int *status)
 381 {
 382         int ret;
 383
 384         DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
 385         for (;;) {
 386                 pause();
 387                 ret = next_signal();
 388                 if (ret < 0)
 389                         break;
 390                 if (!ret)
 391                         continue;
 392                 if (ret == SIGCHLD) {
 393                         ret = waitpid(pid, status, 0);
 394                         if (ret >= 0)
 395                                 break;
 396                         if (errno != EINTR) { /* error */
 397                                 ret = -ERRNO_TO_DSS_ERROR(errno);
 398                                 break;
 399                         }
 400                 }
 401                 /* SIGINT or SIGTERM */
 402                 DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
 403                 kill(pid, SIGTERM);
 404         }
 405         if (ret < 0)
 406                 make_err_msg("failed to wait for process %d", (int)pid);
 407         else
 408                 log_termination_msg(pid, *status);
 409         return ret;
 410 }
 411
 412 int remove_snapshot(struct snapshot *s)
 413 {
 414         int fds[3] = {0, 0, 0};
 415         assert(!rm_pid);
 416         char *new_name = being_deleted_name(s);
 417         int ret = dss_rename(s->name, new_name);
 418         char *argv[] = {"rm", "-rf", new_name, NULL};
 419
 420         if (ret < 0)
 421                 goto out;
 422         DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval);
 423         stop_rsync_process();
 424         ret = dss_exec(&rm_pid, argv[0], argv, fds);
 425 out:
 426         free(new_name);
 427         return ret;
 428 }
 429
 430 /*
 431  * return: 0: no redundant snapshots, 1: rm process started, negative: error
 432  */
 433 int remove_redundant_snapshot(struct snapshot_list *sl)
 434 {
 435         int ret, i, interval;
 436         struct snapshot *s;
 437         unsigned missing = 0;
 438
 439         DSS_INFO_LOG("looking for intervals containing too many snapshots\n");
 440         for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) {
 441                 unsigned keep = num_snapshots(interval);
 442                 unsigned num = sl->interval_count[interval];
 443                 struct snapshot *victim = NULL, *prev = NULL;
 444                 int64_t score = LONG_MAX;
 445
 446                 if (keep >= num)
 447                         missing += keep - num;
 448                 DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
 449                         interval, keep, num, missing);
 450                 if (keep + missing >= num)
 451                         continue;
 452                 /* redundant snapshot in this interval, pick snapshot with lowest score */
 453                 FOR_EACH_SNAPSHOT(s, i, sl) {
 454                         int64_t this_score;
 455
 456                         //DSS_DEBUG_LOG("checking %s\n", s->name);
 457                         if (s->interval > interval) {
 458                                 prev = s;
 459                                 continue;
 460                         }
 461                         if (s->interval < interval)
 462                                 break;
 463                         if (!victim) {
 464                                 victim = s;
 465                                 prev = s;
 466                                 continue;
 467                         }
 468                         assert(prev);
 469                         /* check if s is a better victim */
 470                         this_score = s->creation_time - prev->creation_time;
 471                         assert(this_score >= 0);
 472                         //DSS_DEBUG_LOG("%s: score %lli\n", s->name, (long long)score);
 473                         if (this_score < score) {
 474                                 score = this_score;
 475                                 victim = s;
 476                         }
 477                         prev = s;
 478                 }
 479                 assert(victim);
 480                 if (conf.dry_run_given) {
 481                         dss_msg("%s would be removed (interval = %i)\n",
 482                                 victim->name, victim->interval);
 483                         continue;
 484                 }
 485                 ret = remove_snapshot(victim);
 486                 return ret < 0? ret : 1;
 487         }
 488         return 0;
 489 }
 490
 491 int remove_outdated_snapshot(struct snapshot_list *sl)
 492 {
 493         int i, ret;
 494         struct snapshot *s;
 495
 496         DSS_INFO_LOG("looking for snapshots belonging to intervals greater than %d\n",
 497                 conf.num_intervals_arg);
 498         FOR_EACH_SNAPSHOT(s, i, sl) {
 499                 if (s->interval <= conf.num_intervals_arg)
 500                         continue;
 501                 if (conf.dry_run_given) {
 502                         dss_msg("%s would be removed (interval = %i)\n",
 503                                 s->name, s->interval);
 504                         continue;
 505                 }
 506                 ret = remove_snapshot(s);
 507                 if (ret < 0)
 508                         return ret;
 509                 return 1;
 510         }
 511         return 0;
 512 }
 513
 514 int handle_rm_exit(int status)
 515 {
 516         int es, ret;
 517
 518         if (!WIFEXITED(status)) {
 519                 make_err_msg("rm process %d died involuntary", (int)rm_pid);
 520                 ret = -E_INVOLUNTARY_EXIT;
 521                 goto out;
 522         }
 523         es = WEXITSTATUS(status);
 524         if (es) {
 525                 make_err_msg("rm process %d returned %d", (int)rm_pid, es);
 526                 ret = -E_BAD_EXIT_CODE;
 527                 goto out;
 528         }
 529         ret = 1;
 530         rm_pid = 0;
 531 out:
 532         return ret;
 533 }
 534
 535 int wait_for_rm_process(void)
 536 {
 537         int status, ret = wait_for_process(rm_pid, &status);
 538
 539         if (ret < 0)
 540                 return ret;
 541         return handle_rm_exit(status);
 542 }
 543
 544 void kill_process(pid_t pid)
 545 {
 546         if (!pid)
 547                 return;
 548         DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid);
 549         kill(pid, SIGTERM);
 550 }
 551
 552 int check_config(void)
 553 {
 554         if (conf.unit_interval_arg <= 0) {
 555                 make_err_msg("bad unit interval: %i", conf.unit_interval_arg);
 556                 return -E_INVALID_NUMBER;
 557         }
 558         DSS_DEBUG_LOG("unit interval: %i day(s)\n", conf.unit_interval_arg);
 559         if (conf.num_intervals_arg <= 0) {
 560                 make_err_msg("bad number of intervals  %i", conf.num_intervals_arg);
 561                 return -E_INVALID_NUMBER;
 562         }
 563         DSS_DEBUG_LOG("number of intervals: %i\n", conf.num_intervals_arg);
 564         return 1;
 565 }
 566
 567 /* exits on errors */
 568 void parse_config_file(int override)
 569 {
 570         int ret;
 571         char *config_file;
 572         struct stat statbuf;
 573         char *old_logfile_arg = NULL;
 574         int old_daemon_given = 0;
 575
 576         if (conf.config_file_given)
 577                 config_file = dss_strdup(conf.config_file_arg);
 578         else {
 579                 char *home = get_homedir();
 580                 config_file = make_message("%s/.dssrc", home);
 581                 free(home);
 582         }
 583         if (override) { /* SIGHUP */
 584                 if (conf.logfile_given)
 585                         old_logfile_arg = dss_strdup(conf.logfile_arg);
 586                 old_daemon_given = conf.daemon_given;
 587         }
 588
 589         ret = stat(config_file, &statbuf);
 590         if (ret && conf.config_file_given) {
 591                 ret = -ERRNO_TO_DSS_ERROR(errno);
 592                 make_err_msg("failed to stat config file %s", config_file);
 593                 goto out;
 594         }
 595         if (!ret) {
 596                 struct cmdline_parser_params params = {
 597                         .override = override,
 598                         .initialize = 0,
 599                         .check_required = 1,
 600                         .check_ambiguity = 0
 601                 };
 602                 cmdline_parser_config_file(config_file, &conf, &params);
 603         }
 604         ret = check_config();
 605         if (ret < 0)
 606                 goto out;
 607         if (override) {
 608                 /* don't change daemon mode on SIGHUP */
 609                 conf.daemon_given = old_daemon_given;
 610                 close_log(logfile);
 611                 logfile = NULL;
 612                 if (conf.logfile_given)
 613                         free(old_logfile_arg);
 614                 else if (conf.daemon_given) { /* re-use old logfile */
 615                         conf.logfile_arg = old_logfile_arg;
 616                         conf.logfile_given = 1;
 617                 }
 618         }
 619         if (conf.logfile_given) {
 620                 logfile = open_log(conf.logfile_arg);
 621                 log_welcome(conf.loglevel_arg);
 622         }
 623         ret = dss_chdir(conf.dest_dir_arg);
 624 out:
 625         free(config_file);
 626         if (ret >= 0)
 627                 return;
 628         log_err_msg(EMERG, -ret);
 629         exit(EXIT_FAILURE);
 630 }
 631
 632 void handle_sighup(void)
 633 {
 634         DSS_NOTICE_LOG("SIGHUP\n");
 635         parse_config_file(1);
 636 }
 637
 638 int rename_incomplete_snapshot(int64_t start)
 639 {
 640         char *old_name, *new_name;
 641         int ret;
 642
 643         ret = complete_name(start, get_current_time(), &new_name);
 644         if (ret < 0)
 645                 return ret;
 646         old_name = incomplete_name(start);
 647         ret = dss_rename(old_name, new_name);
 648         if (ret >= 0)
 649                 DSS_NOTICE_LOG("%s -> %s\n", old_name, new_name);
 650         free(old_name);
 651         free(new_name);
 652         return ret;
 653 }
 654
 655 int handle_rsync_exit(int status)
 656 {
 657         int es, ret;
 658
 659         if (!WIFEXITED(status)) {
 660                 make_err_msg("rsync process %d died involuntary", (int)rsync_pid);
 661                 ret = -E_INVOLUNTARY_EXIT;
 662                 goto out;
 663         }
 664         es = WEXITSTATUS(status);
 665         if (es != 0 && es != 23 && es != 24) {
 666                 make_err_msg("rsync process %d returned %d", (int)rsync_pid, es);
 667                 ret = -E_BAD_EXIT_CODE;
 668                 goto out;
 669         }
 670         ret = rename_incomplete_snapshot(current_snapshot_creation_time);
 671 out:
 672         rsync_pid = 0;
 673         current_snapshot_creation_time = 0;
 674         rsync_stopped = 0;
 675         return ret;
 676 }
 677
 678 int get_newest_complete(const char *dirname, void *private)
 679 {
 680         struct edge_snapshot_data *esd = private;
 681         struct snapshot s;
 682         int ret = is_snapshot(dirname, esd->now, &s);
 683
 684         if (ret <= 0)
 685                 return 1;
 686         if (s.flags != SS_COMPLETE) /* incomplete or being deleted */
 687                 return 1;
 688         if (s.creation_time < esd->snap.creation_time)
 689                 return 1;
 690         free(esd->snap.name);
 691         esd->snap = s;
 692         return 1;
 693 }
 694
 695 __malloc char *name_of_newest_complete_snapshot(void)
 696 {
 697         struct edge_snapshot_data esd = {
 698                 .now = get_current_time(),
 699                 .snap = {.creation_time = -1}
 700         };
 701         for_each_subdir(get_newest_complete, &esd);
 702         return esd.snap.name;
 703 }
 704
 705 void create_rsync_argv(char ***argv, int64_t *num)
 706 {
 707         char *logname, *newest = name_of_newest_complete_snapshot();
 708         int i = 0, j;
 709
 710         *argv = dss_malloc((15 + conf.rsync_option_given) * sizeof(char *));
 711         (*argv)[i++] = dss_strdup("rsync");
 712         (*argv)[i++] = dss_strdup("-aq");
 713         (*argv)[i++] = dss_strdup("--delete");
 714         for (j = 0; j < conf.rsync_option_given; j++)
 715                 (*argv)[i++] = dss_strdup(conf.rsync_option_arg[j]);
 716         if (newest) {
 717                 DSS_INFO_LOG("using %s as reference snapshot\n", newest);
 718                 (*argv)[i++] = make_message("--link-dest=../%s", newest);
 719                 free(newest);
 720         } else
 721                 DSS_INFO_LOG("no previous snapshot found\n");
 722         if (conf.exclude_patterns_given) {
 723                 (*argv)[i++] = dss_strdup("--exclude-from");
 724                 (*argv)[i++] = dss_strdup(conf.exclude_patterns_arg);
 725
 726         }
 727         logname = dss_logname();
 728         if (conf.remote_user_given && !strcmp(conf.remote_user_arg, logname))
 729                 (*argv)[i++] = dss_strdup(conf.source_dir_arg);
 730         else
 731                 (*argv)[i++] = make_message("%s@%s:%s/", conf.remote_user_given?
 732                         conf.remote_user_arg : logname,
 733                         conf.remote_host_arg, conf.source_dir_arg);
 734         free(logname);
 735         *num = get_current_time();
 736         (*argv)[i++] = incomplete_name(*num);
 737         (*argv)[i++] = NULL;
 738         for (j = 0; j < i; j++)
 739                 DSS_DEBUG_LOG("argv[%d] = %s\n", j, (*argv)[j]);
 740 }
 741
 742 void free_rsync_argv(char **argv)
 743 {
 744         int i;
 745         for (i = 0; argv[i]; i++)
 746                 free(argv[i]);
 747         free(argv);
 748 }
 749
 750 int create_snapshot(char **argv)
 751 {
 752         int fds[3] = {0, 0, 0};
 753         char *name = incomplete_name(current_snapshot_creation_time);
 754
 755         DSS_NOTICE_LOG("creating new snapshot %s\n", name);
 756         free(name);
 757         return dss_exec(&rsync_pid, argv[0], argv, fds);
 758 }
 759
 760 void compute_next_snapshot_time(struct snapshot_list *sl)
 761 {
 762         struct timeval now, unit_interval = {.tv_sec = 24 * 3600 * conf.unit_interval_arg},
 763                 tmp, diff;
 764         int64_t x = 0;
 765         unsigned wanted = num_snapshots(0), num_complete_snapshots = 0;
 766         int i, ret;
 767         struct snapshot *s;
 768
 769         gettimeofday(&now, NULL);
 770         FOR_EACH_SNAPSHOT(s, i, sl) {
 771                 if (!(s->flags & SS_COMPLETE))
 772                         continue;
 773                 num_complete_snapshots++;
 774                 x += s->completion_time - s->creation_time;
 775         }
 776         assert(x >= 0);
 777         if (num_complete_snapshots)
 778                 x /= num_complete_snapshots; /* avg time to create one snapshot */
 779         x *= wanted; /* time to create all snapshots in interval 0 */
 780         tmp.tv_sec = x;
 781         tmp.tv_usec = 0;
 782         ret = tv_diff(&unit_interval, &tmp, &diff); /* time between creation */
 783         if (ret < 0) {
 784                 next_snapshot_time = now;
 785                 return;
 786         }
 787         tv_divide(wanted, &diff, &tmp);
 788         tv_add(&now, &tmp, &next_snapshot_time);
 789 }
 790
 791 void handle_signal(void)
 792 {
 793         int sig, ret = next_signal();
 794
 795         if (ret <= 0)
 796                 goto out;
 797         sig = ret;
 798         switch (sig) {
 799                 int status;
 800                 pid_t pid;
 801         case SIGINT:
 802         case SIGTERM:
 803                 restart_rsync_process();
 804                 kill_process(rsync_pid);
 805                 kill_process(rm_pid);
 806                 exit(EXIT_FAILURE);
 807         case SIGHUP:
 808                 handle_sighup();
 809                 ret = 1;
 810                 break;
 811         case SIGCHLD:
 812                 ret = reap_child(&pid, &status);
 813                 if (ret <= 0)
 814                         break;
 815                 assert(pid == rsync_pid || pid == rm_pid);
 816                 if (pid == rsync_pid)
 817                         ret = handle_rsync_exit(status);
 818                 else
 819                         ret = handle_rm_exit(status);
 820         }
 821 out:
 822         if (ret < 0)
 823                 log_err_msg(ERROR, -ret);
 824 }
 825
 826 int get_oldest(const char *dirname, void *private)
 827 {
 828         struct edge_snapshot_data *esd = private;
 829         struct snapshot s;
 830         int ret = is_snapshot(dirname, esd->now, &s);
 831
 832         if (ret <= 0)
 833                 return 1;
 834         if (s.creation_time > esd->snap.creation_time)
 835                 return 1;
 836         free(esd->snap.name);
 837         esd->snap = s;
 838         return 1;
 839 }
 840
 841 int remove_oldest_snapshot()
 842 {
 843         int ret;
 844         struct edge_snapshot_data esd = {
 845                 .now = get_current_time(),
 846                 .snap = {.creation_time = LLONG_MAX}
 847         };
 848         for_each_subdir(get_oldest, &esd);
 849         if (!esd.snap.name) /* no snapshot found */
 850                 return 0;
 851         DSS_INFO_LOG("oldest snapshot: %s\n", esd.snap.name);
 852         ret = 0;
 853         if (esd.snap.creation_time == current_snapshot_creation_time)
 854                 goto out; /* do not remove the snapshot currently being created */
 855         ret = remove_snapshot(&esd.snap);
 856 out:
 857         free(esd.snap.name);
 858         return ret;
 859 }
 860
 861 /* TODO: Also consider number of inodes. */
 862 int disk_space_low(void)
 863 {
 864         struct disk_space ds;
 865         int ret = get_disk_space(".", &ds);
 866
 867         if (ret < 0)
 868                 return ret;
 869         if (conf.min_free_mb_arg)
 870                 if (ds.free_mb < conf.min_free_mb_arg)
 871                         return 1;
 872         if (conf.min_free_percent_arg)
 873                 if (ds.percent_free < conf.min_free_percent_arg)
 874                         return 1;
 875         return 0;
 876 }
 877
 878 int try_to_free_disk_space(int low_disk_space, struct snapshot_list *sl)
 879 {
 880         int ret;
 881
 882         ret = remove_outdated_snapshot(sl);
 883         if (ret) /* error, or we are removing something */
 884                 return ret;
 885         /* no outdated snapshot */
 886         ret = remove_redundant_snapshot(sl);
 887         if (ret)
 888                 return ret;
 889         if (!low_disk_space)
 890                 return 0;
 891         DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
 892         ret = remove_oldest_snapshot();
 893         if (ret)
 894                 return ret;
 895         make_err_msg("uhuhu: not enough disk space for a single snapshot");
 896         return  -ENOSPC;
 897 }
 898
 899 int select_loop(void)
 900 {
 901         int ret;
 902         struct timeval tv = {.tv_sec = 0, .tv_usec = 0};
 903         struct snapshot_list sl = {.num_snapshots = 0};
 904
 905         for (;;) {
 906                 struct timeval now, *tvp = &tv;
 907                 fd_set rfds;
 908                 int low_disk_space;
 909                 char **rsync_argv;
 910
 911                 free_snapshot_list(&sl);
 912                 get_snapshot_list(&sl);
 913                 compute_next_snapshot_time(&sl);
 914                 FD_ZERO(&rfds);
 915                 FD_SET(signal_pipe, &rfds);
 916                 if (rsync_pid)
 917                         tv.tv_sec = 60;
 918                 else if (rm_pid)
 919                         tvp = NULL;
 920                 ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
 921                 if (ret < 0)
 922                         return ret;
 923                 if (FD_ISSET(signal_pipe, &rfds)) {
 924                         handle_signal();
 925                         continue;
 926                 }
 927                 if (rm_pid)
 928                         continue;
 929                 ret = disk_space_low();
 930                 if (ret < 0)
 931                         break;
 932                 low_disk_space = ret;
 933                 if (low_disk_space)
 934                         stop_rsync_process();
 935                 ret = try_to_free_disk_space(low_disk_space, &sl);
 936                 if (ret < 0)
 937                         break;
 938                 if (rm_pid)
 939                         continue;
 940                 if (rsync_pid) {
 941                         restart_rsync_process();
 942                         continue;
 943                 }
 944                 /* neither rsync nor rm are running. Start rsync? */
 945                 gettimeofday(&now, NULL);
 946                 if (tv_diff(&next_snapshot_time, &now, &tv) > 0)
 947                         continue;
 948                 create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
 949                 ret = create_snapshot(rsync_argv);
 950                 free_rsync_argv(rsync_argv);
 951                 if (ret < 0)
 952                         break;
 953         }
 954         free_snapshot_list(&sl);
 955         return ret;
 956 }
 957
 958 int com_run(void)
 959 {
 960         int ret;
 961
 962         if (conf.dry_run_given) {
 963                 make_err_msg("dry_run not supported by this command");
 964                 return -E_SYNTAX;
 965         }
 966         ret = install_sighandler(SIGHUP);
 967         if (ret < 0)
 968                 return ret;
 969         return select_loop();
 970 }
 971
 972 void log_disk_space(struct disk_space *ds)
 973 {
 974         DSS_INFO_LOG("free: %uM/%uM (%u%%), %u%% inodes unused\n",
 975                 ds->free_mb, ds->total_mb, ds->percent_free,
 976                 ds->percent_free_inodes);
 977 }
 978
 979 int com_prune(void)
 980 {
 981         int ret;
 982         struct snapshot_list sl;
 983         struct disk_space ds;
 984
 985         ret = get_disk_space(".", &ds);
 986         if (ret < 0)
 987                 return ret;
 988         log_disk_space(&ds);
 989         for (;;) {
 990                 get_snapshot_list(&sl);
 991                 ret = remove_outdated_snapshot(&sl);
 992                 free_snapshot_list(&sl);
 993                 if (ret < 0)
 994                         return ret;
 995                 if (!ret)
 996                         break;
 997                 ret = wait_for_rm_process();
 998                 if (ret < 0)
 999                         goto out;
1000         }
1001         for (;;) {
1002                 get_snapshot_list(&sl);
1003                 ret = remove_redundant_snapshot(&sl);
1004                 free_snapshot_list(&sl);
1005                 if (ret < 0)
1006                         return ret;
1007                 if (!ret)
1008                         break;
1009                 ret = wait_for_rm_process();
1010                 if (ret < 0)
1011                         goto out;
1012         }
1013         return 1;
1014 out:
1015         return ret;
1016 }
1017
1018 int com_create(void)
1019 {
1020         int ret, status;
1021         char **rsync_argv;
1022
1023         create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
1024         if (conf.dry_run_given) {
1025                 int i;
1026                 char *msg = NULL;
1027                 for (i = 0; rsync_argv[i]; i++) {
1028                         char *tmp = msg;
1029                         msg = make_message("%s%s%s", tmp? tmp : "",
1030                                 tmp? " " : "", rsync_argv[i]);
1031                         free(tmp);
1032                 }
1033                 dss_msg("%s\n", msg);
1034                 free(msg);
1035                 return 1;
1036         }
1037         ret = create_snapshot(rsync_argv);
1038         if (ret < 0)
1039                 goto out;
1040         ret = wait_for_process(rsync_pid, &status);
1041         if (ret < 0)
1042                 goto out;
1043         ret = handle_rsync_exit(status);
1044 out:
1045         free_rsync_argv(rsync_argv);
1046         return ret;
1047 }
1048
1049 int com_ls(void)
1050 {
1051         int i;
1052         struct snapshot_list sl;
1053         struct snapshot *s;
1054         get_snapshot_list(&sl);
1055         FOR_EACH_SNAPSHOT(s, i, &sl)
1056                 dss_msg("%u\t%s\n", s->interval, s->name);
1057         free_snapshot_list(&sl);
1058         return 1;
1059 }
1060
1061 __noreturn void clean_exit(int status)
1062 {
1063         free(dss_error_txt);
1064         exit(status);
1065 }
1066 static void setup_signal_handling(void)
1067 {
1068         int ret;
1069
1070         DSS_INFO_LOG("setting up signal handlers\n");
1071         signal_pipe = signal_init(); /* always successful */
1072         ret = install_sighandler(SIGINT);
1073         if (ret < 0)
1074                 goto err;
1075         ret = install_sighandler(SIGTERM);
1076         if (ret < 0)
1077                 goto err;
1078         ret = install_sighandler(SIGCHLD);
1079         if (ret < 0)
1080                 goto err;
1081         return;
1082 err:
1083         DSS_EMERG_LOG("could not install signal handlers\n");
1084         exit(EXIT_FAILURE);
1085 }
1086
1087 int main(int argc, char **argv)
1088 {
1089         int ret;
1090         struct cmdline_parser_params params = {
1091                 .override = 0,
1092                 .initialize = 1,
1093                 .check_required = 0,
1094                 .check_ambiguity = 0
1095         };
1096
1097         cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
1098         parse_config_file(0);
1099         if (conf.daemon_given)
1100                 daemon_init();
1101         setup_signal_handling();
1102         ret = call_command_handler();
1103         if (ret < 0)
1104                 log_err_msg(EMERG, -ret);
1105         clean_exit(ret >= 0? EXIT_SUCCESS : EXIT_FAILURE);
1106 }